Gerry Myerson <gerry@mpce.mq.edu.au> wrote:| | Robin Chapman <rjc@maths.ex.ac.uk> wrote:| >| > My objection to L'Hopital is mainly pedagogical. I've found that| > students immediately latch on to this rule, and will try to use| > it in *every* situation. It's depressing to see them fill three sides| > of A4 with a L'H rule that needs to be iterated a few lines when| > say, a series expansion will do it in two lines.| | I find it even more depressing to see them "use" L'H to evaluate | limit as x -> 0 of (cos x)/x.

An interesting L'Hospital pitfall is the following erroneous deduction